Nighttime Aerial Sprays for Control of Crepuscular Biting Midges in South Carolina.

Nighttime aerial spray applications with naled were conducted to evaluate their efficacy in controlling crepuscular biting midges (Culicoides spp.) in South Carolina, using a US Air Force C-130. Local populations of Culicoides spp. were monitored before and after the sprays with Mosquito Magnet traps to assess the efficacy of postsunset applications. Biting midge populations were consistently decreased by the aerial spray applications in this study. This indicates that nighttime sprays can be used to control these pests, even when their peak flight activity is focused around sunset.

US Department of Defense Support of Civilian Vector Control Operations Following Natural Disasters.

The United States Department of Defense (DoD) employs advanced-degreed entomologists as Preventive Medicine and Public Health Officers in the Army, Navy, and Air Force. While the primary objective of military entomologists is service member health and readiness ("force health protection"), military entomology resources can provide support to civil authorities as directed by the President or Secretary of Defense through Department of Defense Directive 3025.18, Defense Support of Civil Authorities (DSCA). The employment of DSCA is complex and involves the consideration of such factors as the proper request process, funding, legality, risk, appropriateness, and readiness. Once approved and mobilized, however, military preventive medicine assets can be of significant help to civil authorities when dealing with emergency vector control. This paper will address some of the policy issues surrounding the use of DSCA, outline the resources available from the individual military services, and provide examples of DoD contingency vector control support to civil authorities.

Texas Mosquito Control Response Following Hurricane Harvey.

Hurricane Harvey has been recorded as the wettest cyclone in United States history, resulting in devastating and catastrophic flooding for the Texas Gulf Coast. The nature of the path of the hurricane, with multiple landfalls along the Texas Gulf Coast, resulted in the largest aerial mosquito control effort for one single storm. Two mosquito control contractors and the Air Force Aerial Spray Unit of the US Air Force Reserve were used to aerial treat 6,765,971 acres (3,075,441 ha) in 29 of the 60 disaster-declared counties in Texas. During the response, 101,253 liters of Dibrom® (active ingredient [AI]: naled) and 48,735 liters of Duet™ (AI: 1% prallethrin and 5% sumithrin) were used. In 23/29 counties requesting aerial spraying, mosquito control contractors were used to conduct pre- and postaerial application mosquito surveillance. The remaining 6 counties conducted their own surveillance during the response. A total of 105,153 mosquitoes in 7 genera and 35 species were collected during this response with the major floodwater nuisance mosquito being Psorophora columbiae. The most abundant vector mosquito collected was Culex nigripalpus. Duet at the 0.8% and 1% application rates resulted in 49% and 69% control of Ps. columbiae, respectively. Dibrom application resulted in 95% and 93% control of Ps. Columbia and Cx. nigripalpus populations, respectively.

Aerial ULV control of Aedes aegypti with naled (Dibrom) inside simulated rural village and urban cryptic habitats.

We conducted aerial fixed wing ultra low volume (ULV) spray trials with naled to investigate penetration of exposed and simulated cryptic habitat within opened buildings, partially sealed buildings, and outdoor locations targeting sentinel adult Aedes aegypti mosquitoes in north central Florida. Mortality was observed in open and closed buildings and outdoors, even in mosquitoes placed in cryptic habitats. Observations on the impact of building type, mosquito exposure method such as placement in cryptic habitat, and spray nozzle size on mosquito mortality are described and analyzed.

Development of Air Force Aerial Spray Night Operations: High Altitude Swath Characterizations.

Multiple trials were conducted from 2006 to 2014 in an attempt to validate aerial spray efficacy at altitudes conducive to night spray operations using night vision goggles (NVGs). Higher altitude application of pesticide (more than 400 ft (121.9 m) above ground level (AGL)) suggested that effective vector control might be possible under ideal meteorological conditions. A series of lower altitude daytime applications (300 ft (91.4 m) AGL) demonstrated effective and repeatable mortality of target sentinel insects more than 5,000 ft (1,524 m) downwind, and control of natural vector populations. From these results we believe further pursuit of aerial night applications of pesticide using NVGs at 300 ft (91.4 m) AGL by this group is warranted.

Mosquitoes of Thule Air Base, Greenland.

Thule Air Base in western Greenland had a previously uncharacterized mosquito pest problem. Swarms of bloodfeeding mosquitoes have been reported from June to late August, but the species were unknown. We conducted a base-wide mosquito vector survey from June to July 2012. One species of mosquito, Aedes impiger, was collected and > 3,000 were processed for polymerase chain reaction-based virus surveillance. Active mosquito breeding sites were located throughout the base and surrounding valley. Two pools of mosquitoes from Thule Air Base tested positive for an Orthobunyavirus; however, DNA sequencing of the viral amplicons was not complete enough to fully identify the agent.

Seasonal and diel patterns of biting midges (Ceratopogonidae) and mosquitoes (Culicidae) on the Parris Island Marine Corps Recruit Depot.

The Marine Corps Recruit Depot on Parris Island, SC, is surrounded by tidal salt marshes, which are breeding habitats for many pestiferous biting flies. Knowledge of biting fly behavior patterns is needed to develop effective pest management strategies in urban areas adjacent to salt marshes. We measured biting midge (Ceratopogonidae) and mosquito (Culicidae) seasonal abundance and diel activity patterns on Parris Island using CO(2)-baited suction traps from November 2001 - November 2004. Of the three biting midge species collected, Culicoides furens was most abundant (86.2% of total) and was present in high numbers from late March to November. Culicoides hollensis (12.0% of total) was present during spring and fall but absent in summer and winter; and Culicoides melleus (1.7% of total) was present in spring through fall but absent in winter. Abundance of C. furens had a positive linear correlation with air temperature and rainfall. There were nonlinear correlations between air temperature and C. hollensis and C. melleus numbers, which were most abundant at moderate temperatures. Of 18 mosquito species collected, the most abundant were Aedes taeniorhynchus (42.7% of total), Aedes sollicitans (26.3% of total), Culex salinarius (15.6% of total), Culex quinquefasciatus (7.3% of total), and Aedes vexans (5.7% of total); other species comprised <5% of collections. Aedes taeniorhynchus numbers were positively correlated with temperature and rainfall, and Cx. salinarius was correlated with soil moisture. Activity of most biting midges and mosquitoes were highest the first two hours following sunset. Species of biting flies were present in all months, suggesting that year-round control measures are necessary to reduce exposure to potential disease vectors and nuisance biting.

Efficacy of aerial spray applications using fuselage booms on Air Force C-130H aircraft against mosquitoes and biting midges.

The effectiveness of a novel fuselage boom configuration was tested with flat-fan nozzles on U.S. Air Force C-130H aircraft to create ultra-low volume sprays to control mosquitoes (Culicidae) and biting midges (Ceratopogonidae). The mortality of mosquitoes and biting midges in bioassay cages and natural populations, using the organophosphate adulticide, naled, was measured. Mosquitoes in bioassay cages had 100% mortality at 639 m downwind in all single-pass spray trials, and most trials had >90% mortality up to 1491 m downwind. Mosquito mortality was negatively correlated with distance from the spray release point (r2 = 0.38, P < 0.001). The volume median diam of droplets collected was 44 tm at 213 m and decreased to 11 microm at 2130 m downwind of the release point. Droplet density decreased from an average of 18.4 drops/cm2 at 213 m to 2 drops/cm2 at 2130 m. Droplet densities of 10-18 droplets/cm2 were recorded at sampling stations with high mosquito mortality rates (>90%). In wide-area operational applications, numbers of mosquitoes from natural populations 1 wk postspray were 83% (range 55%-95%), lower than prespray numbers (P < 0.05). Biting midge numbers were reduced by 86% (range 53%-97%) on average (P = 0.051) after 7 days. The results of these field trials indicate that the fuselage boom configuration on C-130H aircraft are an effective method to conduct large-scale aerial sprays during military operations and public health emergencies.

Post-hurricane Rita mosquito surveillance and the efficacy of Air Force aerial applications for mosquito control in east Texas.

Post-Hurricane Rita mosquito surveillance was carried out in 4 east Texas counties to determine mosquito abundance, species composition, and need for mosquito control. Subsequently, aerial applications of naled (Dibrom) for mosquito control were made by the Air Force Aerial Spray Flight, while continued surveillance documented the efficacy of the applications. Psorophora columbiae was the predominant species in landing counts. Twenty-two mosquito species were represented in light trap collections with Aedes atlanitcus/tormentor, Culex nigripalpus, Ae. vexans, and Ps. columbiae making up 91% of the total. A total of 102,001 ha (252,052 acres) were aerially treated based on high mosquito abundance, exposure of first responders and residents to nuisance biting, and local interruption of electric utilities. A significant 90% decline in mosquito abundance was observed posttreatment.